Orthodontic brackets are widely used to align teeth through the application of forces selectively provided by interconnected archwires and accessories. Brackets are typically of metal, ceramic or composite construction and are interconnected to either bands or bonding pads for attachment to teeth.
In edgewise brackets, an archwire passes through a labially opening, horizontal slot defined by one or more pair of opposing tie wings. The archwire is preshaped and sized to provide the desired forces. In each bracket, a tie wing pair includes a gingivally extending tie wing and occlusally extending tie wing. Once placed in the slot of one or more pair of tie wings, an archwire is typically restricted therein by a ligating device such as a steel or elastomeric ligature.
As orthodontic treatment objectives and techniques continue to evolve, numerous corresponding edgewise bracket designs and interconnecting accessories have been proposed. Recently, it has been recognized that it is desirable to reduce frictional engagement between the archwire and bracket surfaces defining the archwire slot to facilitate space closure and bodily tooth movement. Similarly, in many situations, it is now a goal to reduce frictional engagement between the archwire and ligating device employed to restrict the archwire within the slot. Such friction reduction can markedly increase the rate of tooth movement and reduce the duration of the orthodontic treatment.
At the same time, patient comfort and ease-of-use considerations have become increasingly important. Patient comfort has been largely addressed by reducing bracket size to yield smaller and more smoothly contoured brackets. Ease-of-use considerations have stimulated bracket designs which facilitate practitioner's bracket placement/use and accommodate plural modalities.
Texturing of the lingual surface of orthodontic brackets has been used to provide improved bonding between the bracket and the tooth to which the bracket is applied. For example, U.S. Pat. No. 5,522,725, incorporated herein by reference, concerns a method of improving the bond strength of a plastic bracket by temporarily heating and then permanently deforming projections located on the base of the bracket. The deformed projections interlock with adhesive when the bracket is bonded to a tooth. U.S. Pat. No. 5,595,484, incorporated herein by reference, discloses a plastic bracket having a metal reinforcement member partly embedded in the bracket body. FIG. 13 of the '484 patent discloses a bracket base having eight recessed discontinuous portions 36 that include molded identification characters 35. U.S. Pat. No. 5,622,494, incorporated herein by reference, discloses several structures, including a spiral-like ridge, concentric rectangles, and a weave pattern. Upon being deformed, each structure creates an undercut structure for forming a mechanical bond with an adhesive. However, this patent and the other patents noted above fail to disclose a base structure that includes lettering, symbols, or numerals that are substantially continuous and that functionally serve as texturing to bond the bracket to a patient's tooth. The present invention, amongst other things as described below, addresses these shortcomings.
The present invention represents significant advances in relation to the above-noted orthodontic bracket considerations, both singularly and combinatively, while maintaining the structural integrity of the bracket.